Thermochemical energy processes
What do you know about BIOMASS? What do you know about its use and clear-energy?
Today, the research of new kinds of feedstock for energy production is based not only for solar and wind power, but also organic matter of many industrial and human waste. Look for vegetables and animal wastes, because they are most diffused feed in the world, a perfect stock of energy.
There are different kinds of treatment for energy production from biomass. The gasification is one of most diffused for the synthesis gas production, due to small use of air in the tank.
The process occurs through the reaction of oxygen and carbon, for the production of CO, and the release of hydrogen atoms from vapor, for the production of H2.
Often, a lot of ash is produced as bed materials. It is burned in a combustion zone quickly linked, and the high temperature of gasification zone is provided from here.
The combustion process is the most important system for energy production, because it is first method to transform a feedstock in heat. Therefore, a combustion system is always linked with other energy production system (as we saw in gasification process) because it can produce heat to power production, through a generator.
The combustion process requires a large amount of oxygen and high temperature and the products are carbon dioxide and water.
A particular process is the pyrolysis. It used in some part of big system, because the main characteristic is the absence of air. It works thanks to high temperature, and transforms the biomass in three different phases of products: charcoal, liquid and gaseous.
Moreover, pyrolysis is one of the most important hydrothermical carbonization (HTC) because it uses high temperature to carbonate production.
The anaerobic digestion is the process which transform fats, protein and sugar in biogas (usually methane). It is composed by three main steps:
- hydrolysis, which produces long chain fatty acids (LCFA), amino acids, glucose and xylose;
- acidogenesis, which transforms LCFA to volatile fatty acids (VFA), acetic acids, hydrogen and carbon monoxide;
- methanogenesis, which produces methane from two different ways.
A lot of parameter must to controlled because the environment have to be ideal for bacterial work. Therefore, it is necessary to control temperature, acidity and all reactants in the system.
The most important pre-treatment of biomass for the anaerobic digestion is the steam explosion. It is a quickly depressurization of wood due to the physical structure of its chains. In fact, wood is composed by cellulose, hemi-cellulose and lignin. The bacteria works only with cellulose (to glucose) and hemi-cellulose (to xylose), and lignin is undegestable for this system.
Through Aspen Plus, non-stoichiometric approach is possible to improve for the determination of a reaction. If the exactly reaction is unknown, it can provide to calculate the amount of reactants, the equilibrium state, and all parameters of different kinds of products.
This is very useful for many application in digestion or energy production, because of the large number of parameters and elements which influence the real system.